From Fellrnr.com, Running tips
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* Charlie, a fit, but not heat acclimatized runner, weighs himself before and after his run and the difference is 8 pounds, which is roughly equivalent to 8 pints of sweat. Charlie had also consumed 80 ounces of Gatorade on the run. This gives an estimate of 8+5=13 pints of sweat. At 0.7 grams of sodium per pint, that’s a total of 9 grams of sodium, which is 23 grams of salt or about 4 teaspoons. The Gatorade provided approximately 1 gram of sodium, or a 1/2 teaspoon.
* For the next run, Charlie changes his drink to add 1/4 teaspoon of extra salt to his Gatorade. He sweats and drinks the same amounts as the previous run. This time, his drink provides him with 4.7 grams of salt, or 3/4 teaspoon of salt.
== More on Hyponatremia ==